This EW-60C Lens Hood for select lenses from Canon is primarily designed to prevent unwanted stray light from entering the lens by extending and shading the end of the lens. In addition, since the end of the lens is extended, you also get the added benefit of some extra protection from accidental impact.
Dedicated lens hoods are designed to match the specific focal length of the lens it was designed for.
Perfect fit for my Canon 18-55mm lens and really helps cut down glare in bright sunlight. It also adds a nice layer of protection to the front of the lens. Great value and easy to attach.